1
|
Qu L, Dahlgren RA, Gan S, Ren M, Chen N, Guo W. Spatial variation of anthropogenic disturbances within watersheds determines dissolved organic matter composition exported to oceans. WATER RESEARCH 2024; 262:122084. [PMID: 39018578 DOI: 10.1016/j.watres.2024.122084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 07/09/2024] [Accepted: 07/10/2024] [Indexed: 07/19/2024]
Abstract
Global land-use changes alter the delivery of fluvial dissolved organic matter (DOM) along land-to-sea continuum. To study how spatial variations in watershed anthropogenic disturbances control chemodiversity and reactivity of DOM exported to oceans, we used fluorescent and ultra-high-resolution mass spectrometry to investigate spatial and seasonal variations of DOM properties along two subtropical coastal rivers with contrasting anthropogenic land-use distributions (North and West tributaries of Jiulong River, southeast China). Dissolved organic carbon (DOC) concentration and humic- and protein-like fluorescent DOM (FDOM) intensities were high in the mixed urban-agricultural impacted upper North River and lower West River. DOM molecular signatures suggested that the urban-sourced DOM is dominated by bio-labile, S-rich compounds, whereas the agricultural-sourced DOM is characterized by a mixture of bio-labile CHONS and bio-refractory CHON. This anthropogenic-induced spatial variation in DOM signatures was especially prominent during the dry season. Molecular analysis indicated that heteroatomic-containing (phosphorus-sulfur-nitrogen) DOM compounds are more biologically degradable, whereas most of the heteroatom-depleted and highly unsaturated CHO was stable during transport. Due to a longer transit distance and reservoir impoundment in North River, the urban-sourced aliphatic compounds were largely microbially removed or transformed into bio-refractory components, resulting in lower DOC fluxes and an increase of recalcitrance in the DOM exported to the ocean. Conversely, shorter transit times for anthropogenic inputs from the middle/lower West River increased watershed yield and export fluxes of DOC with higher bio-lability. Our study documents that transit history plays a crucial role in assessing the fate of anthropogenic DOM along the land-to-ocean continuum.
Collapse
Affiliation(s)
- Liyin Qu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361012, China; National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou 325035, China; Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China
| | - Randy A Dahlgren
- Department of Land, Air and Water Resources, University of California, Davis 95616, USA
| | - Shuchai Gan
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Mingxing Ren
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361012, China
| | - Nengwang Chen
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, College of the Environment and Ecology, Xiamen University, Xiamen 361012, China
| | - Weidong Guo
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361012, China.
| |
Collapse
|
2
|
Li J, Liang E, Deng C, Li B, Cai H, Ma R, Xu Q, Liu J, Wang T. Labile dissolved organic matter (DOM) and nitrogen inputs modified greenhouse gas dynamics: A source-to-estuary study of the Yangtze River. WATER RESEARCH 2024; 253:121318. [PMID: 38387270 DOI: 10.1016/j.watres.2024.121318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 02/07/2024] [Accepted: 02/14/2024] [Indexed: 02/24/2024]
Abstract
Although rivers are increasingly recognized as essential sources of greenhouse gases (GHG) to the atmosphere, few systematic efforts have been made to reveal the drivers of spatiotemporal variations of dissolved GHG (dGHG) in large rivers under increasing anthropogenic stress and intensified hydrological cycling. Here, through a source-to-estuary survey of the Yangtze River in March (spring) and October (autumn) of 2018, we revealed that labile dissolved organic matter (DOM) and nitrogen inputs remarkably modified the spatiotemporal distribution of dGHG. The average partial pressure of CO2 (pCO2), CH4 and N2O concentrations of all sampling sites in the Yangtze River were 1015 ± 225 μatm, and 87.5± 36.5 nmol L-1, and 20.3 ± 6.6 nmol L-1, respectively, significantly lower than the global average. In terms of longitudinal and seasonal variations, higher GHG concentrations were observed in the middle-lower reach in spring. The dominant drivers of spatiotemporal variations in dGHG were labile, protein-like DOM components and nitrogen level. Compared with the historical data of dGHG from published literature, we found a significant increase in N2O concentrations in the Yangtze River during 2004-2018, and the increasing trend was consistent with the rising riverine nitrogen concentrations. Our study emphasized the critical roles of labile DOM and nitrogen inputs in driving the spatial hotspots, seasonal variations and annual trends of dGHG. These findings can contribute to constraining the global GHG budget estimations and controls of GHG emission in large rivers in response to global change.
Collapse
Affiliation(s)
- Jiarui Li
- College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Materials Flux in River Ecosystems, Beijing 100871, PR China
| | - Enhang Liang
- College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Materials Flux in River Ecosystems, Beijing 100871, PR China
| | - Chunfang Deng
- College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Materials Flux in River Ecosystems, Beijing 100871, PR China
| | - Bin Li
- College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Materials Flux in River Ecosystems, Beijing 100871, PR China
| | - Hetong Cai
- College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Materials Flux in River Ecosystems, Beijing 100871, PR China
| | - Ruoqi Ma
- College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Materials Flux in River Ecosystems, Beijing 100871, PR China; General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources, Beijing 100120, PR China
| | - Qiang Xu
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 15030, PR China
| | - Jiaju Liu
- Research Center for Integrated Control of Watershed Water Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
| | - Ting Wang
- College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Materials Flux in River Ecosystems, Beijing 100871, PR China.
| |
Collapse
|
3
|
Zhu Y, Li Y, Wei Y, Norgbey E, Chen Y, Li R, Wang C, Cheng Y, Bofah-Buoh R. Impact of Eucalyptus residue leaching on iron distribution in reservoir sediments assessed by high-resolution DGT technique. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:125718-125730. [PMID: 38001297 DOI: 10.1007/s11356-023-31116-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023]
Abstract
Blackwater occurs every winter in reservoirs with Eucalyptus plantations. The complexation reaction between ferric iron (Fe3+) and Eucalyptus leachate tannic acid from logging residues (especially leaves) is the vital cause of water blackness. However, the effect of Eucalyptus leaf leaching on the dynamic of iron in sediments and its contribution to reservoir blackwater remain unclear. In this study, two experiments were conducted to simulate the early decomposition processes of exotic Eucalyptus and native Pinus massoniana leaves in water (LW) and water-sediment (LWS) systems. In LW, high concentrations of tannic acid (>45.25 mg/L) rapidly leached from the Eucalyptus leaves to the water column, exceeding those of Pinus massoniana leaves (<1.80 mg/L). The chrominance increased from 5~10 to 80~140, and the water body finally appeared brown instead of black after the leaching of Eucalyptus leaves. The chrominance positively correlated with tannic acid concentrations (R=0.970, p<0.01), indicating that tannic acid was vital for the water column's brown color. Different in LWS, blackwater initially emerged near the sediment-water interface (SWI) and extended upward to the entire water column as Eucalyptus leaves leached. Dissolved oxygen (DO) and transmission values in the overlying water declined simultaneously (R>0.77, p<0.05) and were finally below 2.29 mg/L and 10%, respectively. During the leaching of Eucalyptus leaves, the DGT-labile Fe2+ in sediments migrated from deep to surface layers, and the diffusive fluxes of Fe2+ at the SWI increased from 12.42~19.93 to 18.98~26.28 mg/(m2·day), suggesting that sediment released abundant Fe3+ into the aerobic overlying water. Fe3+ was exposed to high concentrations of tannic acid at the SWI and immediately generated the black Fe-tannic acid complex. The results indicated that the supplement of dissolved Fe3+ from sediments is a critical factor for the periodic blackwater in the reservoirs with Eucalyptus plantations. Reducing the cultivation of Eucalyptus in the reservoir catchment is one of the effective ways to alleviate the reservoir blackwater.
Collapse
Affiliation(s)
- Ya Zhu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Yiping Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
| | - Yao Wei
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Eyram Norgbey
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Yu Chen
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Ronghui Li
- Key Laboratory of Disaster Prevention and Structural Safety, Ministry of Education, College of Civil Engineering and Architecture, Guangxi University, Nanning, 530000, China
| | - Can Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Yu Cheng
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Robert Bofah-Buoh
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| |
Collapse
|
4
|
Yi Y, Liu T, Merder J, He C, Bao H, Li P, Li S, Shi Q, He D. Unraveling the Linkages between Molecular Abundance and Stable Carbon Isotope Ratio in Dissolved Organic Matter Using Machine Learning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17900-17909. [PMID: 37079797 DOI: 10.1021/acs.est.3c00221] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Dissolved organic matter (DOM) is a complex mixture of molecules that constitutes one of the largest reservoirs of organic matter on Earth. While stable carbon isotope values (δ13C) provide valuable insights into DOM transformations from land to ocean, it remains unclear how individual molecules respond to changes in DOM properties such as δ13C. To address this, we employed Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to characterize the molecular composition of DOM in 510 samples from the China Coastal Environments, with 320 samples having δ13C measurements. Utilizing a machine learning model based on 5199 molecular formulas, we predicted δ13C values with a mean absolute error (MAE) of 0.30‰ on the training data set, surpassing traditional linear regression methods (MAE 0.85‰). Our findings suggest that degradation processes, microbial activities, and primary production regulate DOM from rivers to the ocean continuum. Additionally, the machine learning model accurately predicted δ13C values in samples without known δ13C values and in other published data sets, reflecting the δ13C trend along the land to ocean continuum. This study demonstrates the potential of machine learning to capture the complex relationships between DOM composition and bulk parameters, particularly with larger learning data sets and increasing molecular research in the future.
Collapse
Affiliation(s)
- Yuanbi Yi
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, Hong Kong SAR, China
| | - Tongcun Liu
- School of Mathematics and Computer Science, Zhejiang A&F University, Hangzhou 311300, China
| | - Julian Merder
- Department of Global Ecology, Carnegie Institution for Science, Stanford, California 94305, United States
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
| | - Hongyan Bao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Penghui Li
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
| | - Siliang Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
| | - Ding He
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, Hong Kong SAR, China
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, Hong Kong SAR, China
| |
Collapse
|
5
|
Zhao C, Xu X, Chen H, Wang F, Li P, He C, Shi Q, Yi Y, Li X, Li S, He D. Exploring the Complexities of Dissolved Organic Matter Photochemistry from the Molecular Level by Using Machine Learning Approaches. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17889-17899. [PMID: 37248194 DOI: 10.1021/acs.est.3c00199] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Dissolved organic matter (DOM) sustains a substantial part of the organic matter transported seaward, where photochemical reactions significantly affect its transformation and fate. The irradiation experiments can provide valuable information on the photochemical reactivity (photolabile, photoresistant, and photoproduct) of molecules. However, the inconsistency of the fate of irradiated molecules among different experiments curtailed our understanding of the roles the photochemical reactions have played, which cannot be properly addressed by traditional approaches. Here, we conducted irradiation experiments for samples from two large estuaries in China. Molecules that occurred in irradiation experiments were characterized by the Fourier transform ion cyclotron resonance mass spectrometry and assigned probabilistic labels to define their photochemical reactivity. These molecules with probabilistic labels were used to construct a learning database for establishing a suitable machine learning (ML) model. We further applied our well-trained ML model to "un-matched" (i.e., not detected in our irradiation experiments) molecules from five estuaries worldwide, to predict their photochemical reactivity. Results showed that numerous molecules with strong photolability can be captured solely by the ML model. Moreover, comparing DOM photochemical reactivity in five estuaries revealed that the riverine DOM chemistry largely determines their subsequent photochemical transformation. We offer an expandable and renewable approach based on ML to compatibly integrate existing irradiation experiments and shed insight into DOM transformation and degradation processes.
Collapse
Affiliation(s)
- Chen Zhao
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| | - Xinyue Xu
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| | - Hongmei Chen
- State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, College of the Environment and Ecology, Xiamen University, Xiamen 361000, China
| | - Fengwen Wang
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Department of Environmental Science, Chongqing University, Chongqing 400030, China
| | - Penghui Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai 519082, China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing 102249, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing 102249, China
| | - Yuanbi Yi
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| | - Xiaomeng Li
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| | - Siliang Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Ding He
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong 999077, China
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 999077, China
| |
Collapse
|
6
|
Zhao C, Hou Y, Wang Y, Li P, He C, Shi Q, Yi Y, He D. Unraveling the photochemical reactivity of dissolved organic matter in the Yangtze river estuary: Integrating incubations with field observations. WATER RESEARCH 2023; 245:120638. [PMID: 37742401 DOI: 10.1016/j.watres.2023.120638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/26/2023]
Abstract
Dissolved organic matter (DOM) sustains a substantial part of the organic matter transported seaward in large estuaries, where photochemical reactions significantly influence its transformation and fate. Irradiation experiments can provide valuable information on the photochemical reactivity (photo-labile, photo-resistant, and photo-product) of molecules. However, previous research paid less attention to exploring the controls of the initial DOM chemistry to irradiation experiments and examining the applicability of their further integration with field research. Here, we conducted irradiation experiments for samples from the freshwater and seawater endmember of the Yangtze River Estuary (YRE), which receives organic matter transport from the largest river in China, the Yangtze River. Molecules that occurred before and after irradiation experiments were characterized by the Fourier transform ion cyclotron resonance mass spectrometry. Results show that both post-irradiation samples have the lower aromaticity degree and reduced oxidation state, while the freshwater endmember sample exhibits more dramatic changes, indicating the controls of parent molecules to the effect of irradiation experiments. Integrating with the "molecular matching" approach, we compared the molecules occurring in field samples with the classified molecules (photo-resistant, photo-labile, and photo-product) acquired from performed irradiation experiments and correlated the relative intensity of photochemical reactivity types with salinity. When applying results from different experiments to conduct "molecular matching", the photo-resistant and photo-labile relative intensity possess consistently positive and negative trends with increasing salinity, respectively. This suggests their reliability for molecular matching applications, while the inconsistent trends for the photo-product relative intensity with salinity suggest its uncertainty in assessing the photo-induced effects. Moreover, the molecular composition within the photochemical reactivity types in field samples also evolved along the salinity gradient and showed similar trends with the DOM changes after experimental irradiation. Despite various factors influencing estimations, it is revealed that a fraction of aromatic molecules and majority of carboxyl-rich alicyclic molecules considered with biologically persistent nature in the YRE freshwater zone are simultaneously not susceptible to photochemical transformation to potentially constitute a long-term marine carbon sink. This study emphasizes the importance and limitations of the combination of field research and laboratory-controlled experiments to provide a better understanding of the crucial role of photochemical reactions in affecting carbon cycling in large estuaries.
Collapse
Affiliation(s)
- Chen Zhao
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yifu Hou
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yuntao Wang
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| | - Penghui Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai 519082, China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing 102249, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing 102249, China
| | - Yuanbi Yi
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China.
| | - Ding He
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China; State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
| |
Collapse
|
7
|
Imtiazy MN, Hunter K, Sereda J, Dirk L, Hudson JJ. Effects of regional climate, hydrology and river impoundment on long-term patterns and characteristics of dissolved organic matter in semi-arid northern plains rivers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 870:161961. [PMID: 36737025 DOI: 10.1016/j.scitotenv.2023.161961] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/28/2023] [Accepted: 01/29/2023] [Indexed: 06/18/2023]
Abstract
Diverse environmental and anthropogenic factors, such as the ongoing reservoir constructions may influence riverine dissolved organic matter (DOM) properties. This has important implications for river water quality, particularly when reservoirs are a source of drinking water. Simultaneous studies of multidecadal trends in dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) are scarce. We studied the patterns in DOC and DON concentration in two major rivers of the South Saskatchewan River (SSR) basin over a 42-year period (1978-2019). We also examined the impact of a large reservoir on riverine DOC properties. Contrary to many studies, we did not find a long-term increase in DOC and DON concentration, and DOC and DON patterns were not always synchronous. In an agriculture dominated watershed like the SSR basin, agricultural land use (e.g., nitrogen-fertilizer application) could influence DOC and DON concentration differently, potentially resulting in asynchronous patterns over time. River discharge was an important driver of DOM patterns. Regional precipitation in the lower SSR basin may also influence DOM patterns in locations where runoff contribution is greater. These regional factors explained greater variability in DOM compared to global scale indices (e.g., Pacific decadal oscillation) due to their direct control on DOM. A travel time corrected approach to account for the lengthy reservoir turnover time showed that a large reservoir caused a reduction in allochthonous DOC characteristics through photodegradation and perhaps, an increase in autochthonous characteristics. Our results illustrate: 1) the increase in DOM concentrations seen in the northern hemisphere is not present in semi-arid prairie rivers, 2) Controls on different DOM components could be different, and 3) large reservoirs may modify riverine DOC composition due to longer water residence time.
Collapse
Affiliation(s)
- Md Noim Imtiazy
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Kristine Hunter
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Jeff Sereda
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada
| | - Leah Dirk
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Jeff J Hudson
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| |
Collapse
|
8
|
Yang C, Li Z, Wang S, Ran F, Nie X, Liu Y, Xiao T. Anthropogenic activities control the source dynamics of sediment organic carbon in the lower reach of an inland river. WATER RESEARCH 2023; 233:119779. [PMID: 36848854 DOI: 10.1016/j.watres.2023.119779] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 02/12/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Sediment organic carbon (SeOC) sources with rich information can be used as a "historical archive" reflecting anthropogenic activities in the catchment, which is crucial to carbon management in the watershed. Anthropogenic activities and hydrodynamic conditions significantly influence the river environment and are reflected by the SeOC sources. However, the key drivers of the SeOC source dynamics are ambiguous, which restricts the behavior of regulating the carbon output of the basin. In this study, sediment cores from the lower reach of an inland river were selected to quantify the SeOC sources based on a centennial scale. A partial least squares path model was used to establish the relationship between anthropogenic activities and hydrological conditions with the SeOC sources. Findings showed that the exogenous advantage of SeOC composition was gradually significant (early period: 54.3%; middle period: 81%; later period: 82%) from the bottom layer to the surface layer of the sediments in the lower reach of the Xiangjiang River. Factors related to anthropogenic activities controlled the external input of SeOC (δ13C: r∂ = -0.94, P < 0.001; δ15N: r∂ = -0.66, P < 0.001). Different anthropogenic activities performed different effects. Land use change aggravated soil erosion and brought more terrestrial organic carbon to the downstream. The variation of grassland carbon input was the most obvious (from 33.6% to 18.4%). In contrast, the reservoir construction intercepted upstream sediments, which might have been the main reason for the slow growth of terrestrial organic carbon input in the downstream in the later period. This study provides a specific grafting for the SeOC records - source changes - anthropogenic activities in the lower reach of the river, which provides scientific basis for watershed carbon management.
Collapse
Affiliation(s)
- Changrong Yang
- School of Geographical Sciences, Hunan Normal University, Changsha 410081, China
| | - Zhongwu Li
- School of Geographical Sciences, Hunan Normal University, Changsha 410081, China; College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
| | - Shilan Wang
- School of Geographical Sciences, Hunan Normal University, Changsha 410081, China
| | - Fengwei Ran
- School of Geographical Sciences, Hunan Normal University, Changsha 410081, China
| | - Xiaodong Nie
- School of Geographical Sciences, Hunan Normal University, Changsha 410081, China.
| | - Yaojun Liu
- School of Geographical Sciences, Hunan Normal University, Changsha 410081, China
| | - Tao Xiao
- School of Geographical Sciences, Hunan Normal University, Changsha 410081, China
| |
Collapse
|
9
|
Wang K, Pang Y, Yi Y, Yang S, Wang Y, He C, Shi Q, He D. Response of dissolved organic matter chemistry to flood control of a large river reservoir during an extreme storm event. WATER RESEARCH 2023; 230:119565. [PMID: 36628866 DOI: 10.1016/j.watres.2023.119565] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/29/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
With the frequent occurrence of extreme floods under global climate change-induced storm events, reservoir operation has been highlighted for river flood control, complicating the transport and transformation of riverine dissolved organic matter (DOM), one of the largest reactive carbon pools on earth. In particular, the response of riverine DOM chemistry to reservoir flood control during extreme storm events is still unclear. To fill this knowledge gap, the mechanism of DOM variation in Yangtze River with the world's largest Three Gorges Reservoir (TGR) operation during an extreme storm event was explored. Optical and molecular properties of DOM varied significantly from upstream to downstream in non-TGR area, while no significant variation in DOM chemistry was observed in TGR area. The results uncovered a short time transformation of DOM from non-TGR area to TGR area, demonstrating that although storm event induced chemodiversity bloom of riverine DOM, flood control of TGR "re-constrained" DOM to more similar chemistry mainly under the influence of turbidity involved DOM transformation (e.g., adsorption/desorption and flocculation). Furthermore, combined with the hydrological information, we found that although TGR temporarily blocked dissolved organic carbon (DOC) flow during the flood event, the abundance of biologically recalcitrant DOC increased in TGR, which would contribute to its further transportation to downstream watershed. This study emphasizes the impact of TGR on extreme storm event-induced DOM dynamics, which also hints a better understanding of the crucial role of anthropogenic activity in affecting carbon cycling under extreme climate change.
Collapse
Affiliation(s)
- Kai Wang
- Organic Geochemistry Unit, School of Earth Sciences, Zhejiang University, Hangzhou, China
| | - Yu Pang
- Organic Geochemistry Unit, School of Earth Sciences, Zhejiang University, Hangzhou, China
| | - Yuanbi Yi
- Department of Ocean Science and the Southern Marine Science and Engineering Guangdong Laboratory Guangzhou, the Hong Kong University of Science and Technology, Hong Kong, Hong Kong SAR, China
| | - Shouye Yang
- State Key Laboratory of Marine Geology, Tongji University, Shanghai, China
| | - Yuntao Wang
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing, China
| | - Ding He
- Department of Ocean Science and the Southern Marine Science and Engineering Guangdong Laboratory Guangzhou, the Hong Kong University of Science and Technology, Hong Kong, Hong Kong SAR, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China; State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China.
| |
Collapse
|
10
|
Begum MS, Park JH, Yang L, Shin KH, Hur J. Optical and molecular indices of dissolved organic matter for estimating biodegradability and resulting carbon dioxide production in inland waters: A review. WATER RESEARCH 2023; 228:119362. [PMID: 36427460 DOI: 10.1016/j.watres.2022.119362] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 10/20/2022] [Accepted: 11/12/2022] [Indexed: 06/16/2023]
Abstract
Biodegradable dissolved organic carbon (BDOC) constitutes the most labile fraction of dissolved organic matter (DOM), which also functions as a source of CO2 emissions from inland waters. However, no systematic review is available on DOM indicators of BDOC and CO2 production potential. Optical and molecular indices can be used to track small changes in DOM composition during biodegradation. In this review, we identified four different methods for measuring BDOC together with their strengths and limitations. In addition, we discuss the potential of using documented optical indices based on absorption and fluorescence spectroscopy and molecular indices based on Fourier transform ion cyclotron mass spectrometry as proxies for estimating BDOC and biodegradation-induced CO2 production based on previously reported relationships in the literature. Many absorbance- and fluorescence-based indices showed inconsistent relationships with BDOC depending on watershed characteristics, hydrology, and anthropogenic impacts. Nevertheless, several indices, including specific UV absorbance at 254 nm (SUVA254), humification index (HIX), and terrestrial humic-like fluorescent DOM (FDOM) components, tended to have negative relationships with BDOC in tropical and temperate watersheds under baseflow or drought periods. Protein-like FDOM exhibited the strongest correlation with BDOC in different systems, except during storms and flood events. Despite the limited number of studies, DOM molecular indices exhibited consistent relationships with BDOC, suggesting that the relative abundance of aliphatic formulas and the molecular lability index could act as reliable proxies. The DOM optical indices explain up to 96% and 78% variability in BDOC and CO2, respectively; nonetheless, there were limited studies on molecular indices, which explain up to 74% variability in BDOC. Based on literature survey, we recommend several sensitive indices such as SUVA254, HIX, and terrestrial humic- and protein-like FDOM, which could be useful indicators of BDOC and dissolved CO2 in inland water. Future research should incorporate a wider range of geographic regions with various land use, hydrology, and anthropogenic disturbances to develop system- or condition-specific DOM optical or molecular proxies for better prediction of BDOC and CO2 emissions.
Collapse
Affiliation(s)
- Most Shirina Begum
- Department of Environment and Energy, Sejong University, Seoul 05006, South Korea
| | - Ji-Hyung Park
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul 03760, South Korea
| | - Liyang Yang
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou, Fujian, China
| | - Kyung Hoon Shin
- Department of Marine Science and Convergence Engineering, Hanyang University, Ansan, Gyeonggi do 15588, South Korea
| | - Jin Hur
- Department of Environment and Energy, Sejong University, Seoul 05006, South Korea.
| |
Collapse
|
11
|
Zhang W, Zhu G, Qiu D, Liu Y, Sang L, Lin X, Ma H, Zhao K, Xu Y. Effects of agricultural activities on hydrochemistry in the Shiyang River Basin, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:12269-12282. [PMID: 36107297 DOI: 10.1007/s11356-022-22914-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 09/03/2022] [Indexed: 06/15/2023]
Abstract
Agricultural water accounts for more than 80% of the available water in arid areas. Agricultural activities have a great impact on surface water and groundwater. If the impact of agricultural activities on hydrochemistry is not prevented, the risk of water quality change in arid areas may be greatly intensified. Based on the hydrochemical data of the whole Shiyang River Basin from April 2014 to October 2019, this paper analyzes the impact of agricultural activities on hydrochemistry in the basin. The results show that (i) in the middle and lower reaches of farmland with high intensity of agricultural activities, the ion concentration of groundwater in summer and autumn is significantly higher than that in winter and spring due to the influence of irrigation; (ii) the runoff ion concentration in the backflow of the river reaches recharged by irrigation water is significantly higher than that of other reaches; (iii) due to strong evaporation, different types of reservoirs will lead to an overall increase in ion concentration, which is more obvious in plain reservoirs and river tail lakes. In addition, the reservoirs have a certain removal effect on nitrates.
Collapse
Affiliation(s)
- Wenhao Zhang
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China
| | - Guofeng Zhu
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China.
- State Key Laboratory of Cryosphere Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
| | - Dongdong Qiu
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China
| | - Yuwei Liu
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China
| | - Liyuan Sang
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China
| | - Xinrui Lin
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China
| | - Huiying Ma
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China
| | - Kailiang Zhao
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China
| | - Yuanxiao Xu
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China
| |
Collapse
|
12
|
Qu L, He C, Wu Z, Dahlgren RA, Ren M, Li P, Shi Q, Li Y, Chen N, Guo W. Hypolimnetic deoxygenation enhanced production and export of recalcitrant dissolved organic matter in a large stratified reservoir. WATER RESEARCH 2022; 219:118537. [PMID: 35526431 DOI: 10.1016/j.watres.2022.118537] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 06/14/2023]
Abstract
Global impoundment of river systems represents a major anthropogenic forcing to carbon cycling in reservoirs with seasonal thermal stratification. Currently, a quantitative and mechanistic understanding of how hypolimnetic deoxygenation in stratified reservoirs alters dissolved organic matter (DOM) cycling and lateral transport along the river continuum remains unresolved. Herein, we used optical and high-resolution mass spectrometric analyses to track seasonal and spatial compositional changes of DOM from a large, subtropical impounded river in southeast China. Aliphatic compounds were contributed by algal blooms to epilimnetic DOM during the spring/summer and by baseflow to the overall DOM pool during low-discharge periods. Deoxygenation-driven hypolimnetic mineralization enhanced in situ production of bio-refractory molecules and humic-like fluorescent DOM (FDOMH) by utilizing bio-labile DOM and settling biogenic particles during periods of stratification. Production efficiency of hypolimnetic FDOMH was 159-444% higher than that of the global dark ocean, and was strongly regulated by temperature and possibly substrate supply. The in situ production rate of hypolimnetic FDOMH was four to five orders-of-magnitude higher than the dark ocean, with much faster turnover rates in dark inland waters versus the dark ocean. Collectively, these findings indicate that the hypolimnion is a hotspot for microbial carbon transformations, and hence an important source and pool of refractory DOM in aquatic systems. The lateral FDOMH flux increased 10.8-32.1% due to hypolimnetic reservoir release during periods of stratification, highlighting the importance of incorporating hypolimnetic carbon transformations into models for carbon cycling of inland waters and the land-sea interface.
Collapse
Affiliation(s)
- Liyin Qu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361012, China; Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen 361012, China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing 102249, China
| | - Zetao Wu
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen 361012, China
| | - Randy A Dahlgren
- Department of Land, Air and Water Resources, University of California, Davis 95616, USA
| | - Mingxing Ren
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361012, China; Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen 361012, China
| | - Penghui Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing 102249, China
| | - Yan Li
- National Observation and Research Station for the Taiwan Strait Marine Ecosystem, Xiamen University, Xiamen 361012, China
| | - Nengwang Chen
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361012, China; Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen 361012, China; National Observation and Research Station for the Taiwan Strait Marine Ecosystem, Xiamen University, Xiamen 361012, China.
| | - Weidong Guo
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361012, China; Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen 361012, China; National Observation and Research Station for the Taiwan Strait Marine Ecosystem, Xiamen University, Xiamen 361012, China.
| |
Collapse
|